Devils Postpile National Monument

[Fig. 42(6)]
The Devils Postpile offers visitors an outdoor classroom in volcanic history
of the Sierra Nevada. The Postpile basalt has been studied and analyzed
for many years by many people because it is such a spectacular sight. Hundreds
of individual, vertical basalt columns came together as a single formation.
They look as though someone purposely tried to create a bizarre backdrop
for a horror movie.

Around the Postpile, visitors can find waterfalls, dense forest, and many
other volcanic formations. The 100,000 people who come to this area each
year are usually headed for the Postpile to see one of the famous columns.

The columns have an average diameter of about 24 inches and some are as
long as 60 feet. They are the remains of a lava flow that probably occurred
about 100,000 years ago. For many years, the Postpile was mistakenly dated
at 600,000 years old. More recent methods of dating the rock indicate it
is much younger.

Though the Postpile began as a molten mass, it shrank as it cooled, and
it began to crack. Temperatures inside the lava bed were consistent enough
to allow the cooling basalt to form six-sided columns. The Postpile's regularity
of shape is probably its most remarkable feature. Temperatures are rarely
consistent enough to form the columns seen at the Postpile.

The Postpile is a remnant of a much larger flow. It was perhaps 400 feet
deep, emanating from the glaciated valley of the San Joaquin River's Middle
Fork. The basalt lava probably filled the valley for about 3 miles, though
no one knows for sure. Later glaciers pulverized most of the lava formations
and stream erosion carried away other parts of it. There are indications
that the smallest of the ice flows was 1,000 feet thick.

In the 10,000 to 12,000 years that have passed since the last glacier, columns
have fallen from the formation, creating a heap of broken rock at the base
of the Postpile. On top of the formation, visitors will see how the glaciers
polished the rock. The top of the Postpile is probably the most spectacular
angle for visitors to see.

This striking feature was hardly mentioned in the literature of the late
nineteenth century. Little is known about the Postpile before the turn of
the century. Miners were active in the area. Red-bearded "Red"
Sotcher settled into nearby Reds Meadow in the late 1870s, but history does
not connect him with the Postpile.

The feature was known locally in the 1890s as the Devils Woodpile. It was
first recognized as the Devils Postpile in 1901 on various maps. The Postpile
was part of Yosemite National Park in the late 1800s when Congress designated
its boundaries. It was removed from the park in 1905 when Congress removed
500 square miles from the park under pressure from mining and lumber lobbying
interests.

By 1910, a proposal was made to dynamite the Postpile and use it dam the
San Joaquin River. Members of the Sierra Club and University of California
professor Joseph LeConte, who was also a mountaineer, successfully campaigned
against the project. On July 6, 1911, President William Howard Taft proclaimed
the area a national monument and extended full protection of the federal
government.

The typical Eastern Sierra forest greets hikers as they make their way to
the Postpilered fir (Abies magnifica), Jeffrey pine (Pinus
jeffreyi), and lodgepole pine (Pinus murrayana). The slender
cinquefoil (Potentilla gracilis ssp. nuttalii) is particularly
noticeable in this area, along with alpine shooting star (Dodecatheon
alpinum) in August. For bird watchers, look for the dark-eyed junco
(Junco oreganus) and the white-crowned sparrow (Zonotrichia leucophrys)
in the summer months.

Management of the monument can be a bit confusing. It is almost completely
surrounded by the Inyo National Forest, yet Inyo officials have nothing
to do with the management. Inyo officials can answer any of your questions,
but Sequoia National Park on the western slope of the Sierra manages the
monument.

To approach the Postpile, visitors need to enter from Inyo National Forest
to the east. In the short hike, visitors pass from the arid Eastern Sierra
to the lusher western slope. Besides the imposing and irregular outcroppings
of granite along the way, the geology includes pumice and some basalt.

Directions: Drive south about 25 miles from Lee Vining on Highway
395 to the Mammoth Lakes turnoff or State Route 203. Turn right on 203,
drive 3.7 mileswhich will take you through the town of Mammoth Lakesto
a junction with Minaret Summit Road, which forks to the right toward the
Devils Postpile National Monument. Take the right fork and drive about
5.6 miles to the monument entrance. Walk along trail from the parking
lot for about 0.4 mile to the Postpile.

Rainbow Falls

[Fig. 42(7)]
People stand at Rainbow Falls in summer around the noon hour and just watch
the rainbows forming in the constant mist. The San Joaquin River plunges
101 feet down Rainbow Falls in a thundering crescendo all through the summer.
There is no shortage of water and, most days, there is no shortage of people.
Don't expect to get away from the crowds here.

The hike to the falls from the Devils Postpile takes visitors through the
shade of white fir (Abies concolor). Depending on the time of year,
the wildflowers can be dazzling in the moist meadows. Look for the broad-seeded
rockcress (Arabis platysperma) in the rock crannies. The cutleaf
daisy (Erigeron compositus) and the shaggy hawkweed (Hieracium
horridum) are also seen in this area.

There's a bonus when you hike into the falls: You'll be going downhill.
However, remind the children that they will be gaining about 300 feet in
elevation on the way back. Bring the camera and a sandwich, but don't get
too close to the falls or the slippery rocks around them.

Directions: From the Devils Postpile National Monument, hike
downstream along the San Joaquin River. The signs at the Postpile will
direct you to the trail for Rainbow Falls.